1. Field of the Invention
The present invention relates generally to computer networks and, more particularly, to networks in which devices communicate in ad hoc fashion to transfer data.
2. Description of the Related Art
The phrase “computer network” generally refers to a collection of computers that communicate with each other over a shared network medium. The computers can comprise all manner of processing devices that can communicate using an appropriate network protocol, such as laptop computers, hand-held devices, personal digital assistants (PDAs), and the like.
The shared medium for the network is often a sequence of wired connections, such as electrically conductive wiring or cabling. The medium can include optical fiber connections. The network shared medium can also comprise electromagnetic spectrum, such as communications using satellites, terrestrial towers, or other radio frequency (RF) connections.
Networks are useful for sharing data (including messages, audio information, video information, and documents in digital form) among online computers that comprise nodes of the network. When a user is “online”, the user is actively communicating over the network medium and is capable of communicating with one or more other computers that are also connected to the shared medium. Users who are not online (i.e., at computers that are not nodes of a network) cannot send or receive messages over the network. Computer users who are not online are generally said to be “offline”.
In the computer gaming context, it is desirable to share data such as game scores, player rankings, and tournament associations. For example, U.S. patent application number 2002/0188360 to Muramori describes a system in which network game tournaments can be organized via registration of competitions. A player can play offline, without interaction with other players, and the offline player's individually-achieved score can be uploaded to the network later, when the player completes login to the network. In this way, players can get online and can then compare scores achieved by other players, view rankings, check tournament results, and the like. Any player with access to the appropriate network (such as the Internet) can participate in the network game tournament system. Networks with fixed resources, such as servers whose physical location does not change, will be referred to as fixed networks.
Mobile devices, such as network-enabled wireless handheld devices and cell phones, or laptop computers, can connect to a network at different places and at different times. They can operate offline and can connect online later, for network communications. In this document, mobile devices will also be referred to as wireless devices. Computing devices that are connected to a network through a wired or cable connector from the device itself will be referred to as wired devices.
Ad hoc networks (also called mesh networks) are created when a group of devices are in direct communication with each other at the same time (comprising a communication session) after a setup process in which the devices negotiate their network addresses for communication. That is, the members of the ad hoc network communicate with each other in real time, and the paths or links over which the ad hoc members communicate are established in a negotiation or setup procedure in which the members obtain a network address. The ad hoc network paths for communication are active while the members are online and in direct communication with each other, and otherwise the links do not exist. Thus, an ad hoc network is in contrast to a fixed network, in which network members communicate over network infrastructure through fixed network addresses. In any network environment, ad hoc or fixed, the communicating members can be wireless devices or wired devices.
Examples of fixed wireless networks include WLAN or “WiFi” networks that communicate through an access point over the IEEE 802.11 standard, as well as Bluetooth networks. For example, a laptop computer user can communicate wirelessly with a network access point such as a WiFi router, which itself might be connected to a high speed data line via copper coaxial cable, which ultimately travels over optical fiber to an Internet server. The network access point will typically assign a fixed network address to the laptop.
Alternatively, for an ad hoc network environment, two wireless devices may begin communications by broadcasting their presence and, upon detecting the presence of the other, the two may complete processing to establish wireless communications with each other. Such an arrangement is said to comprise a wireless ad hoc network. By means of such an ad hoc network, the two wireless devices can communicate with each other. When the devices break off communications, such as when one or both leave the vicinity of the other, or when one or both shut down, then the ad hoc network ceases to exist.
Some mobile devices are capable of multi-mode network operation. For example, some devices are capable of three modes of operation: (a) offline operation, in which a player might use the mobile device to play a game in solitude, without active connection to a network of any kind, (b) online operation to a fixed network infrastructure, such as where the user is connected to other players via a network (such as the Internet) and engages in interactive gaming communication with the other players, and (c) ad hoc network operation, in which users can be in direct communication with other players to establish an ad hoc network for gaming amongst the directly communicating players.
Although members of ad hoc networks can participate in data exchange between each other while they are connected together, they cannot exchange data with users to whom they are not actively connected. To effect a data exchange, the sending user and the receiving user must be actively communicating with each other at the same time. When they are actively communicating, they comprise an ad hoc network over which they can exchange data. Alternatively, if the sending user and the receiving user each have access to a fixed network, such as the Internet, the data can be exchanged over two links, or “hops”. First, the sending user can send data to the network, where it can be routed to a server or temporarily stored. The data can then be forwarded from the server over the Internet, or retrieved from storage, for reception at the receiving user.
Not all users who can connect to others via ad hoc networks can also connect to others via conventional networks. For example, access to the Internet generally requires that a user establish an appropriate service account with an access provider. Such service accounts generally are fee-based and require payment of access charges or subscription fees. Consequently, only those ad hoc users who have multi-mode devices and who pay for Internet access will be able to get online, notwithstanding their ability to communicate directly with others over an ad hoc network connection.
It would be desirable to permit greater flexibility in exchanging data among mobile ad hoc users who are not necessarily directly connected to intended recipients or to the online network.
Thus, there is a need for an improved, more efficient data exchange technique across offline, online, and ad hoc operating environments. The present invention satisfies this need.